A halide perovskite/lead sulfide heterostructure with enhanced photoelectrochemical performance for the sensing of alkaline phosphatase (ALP)

For the construction of halide perovskite-based photoelectrochemical (PEC) biosensors in aqueous solution, the balance between retaining the excellent photoelectric performances of the halide perovskite and the protective modification of the halide perovskite has always been a challenging problem. In this work, a simple and sensitive photoelectrochemical biosensor based on inorganic halide perovskite CsPbBr3 as the photoactive material for the detection of alkaline phosphatase (ALP) was reported. The substrate sodium thiophosphate (Na3SPO3) can be catalyzed by ALP to produce hydrogen sulfide (H2S), which can react with the lead site on the surface of the CsPbBr3 film to form lead sulfide (PbS), resulting in a stable heterostructure and enhanced photocurrent intensity. The possible mechanism of enhanced photocurrent response of CsPbBr3/PbS heterojunctions was studied in detail. This work paves a new way for applying halide perovskites in different biosensor designs.